Apparatus for folding leading flaps



Oct. 28, 1958 R. A. LABO MBARDE 2,857,827

, APPARATUS FOR FOLDING LEADING FLAPS Filed Aug. 9, 1954 3 Sheets-Sheet 1 LC$D 2%! 23 5 6'0 "50 7 2'8 $2 0 3 32/? 1 119.1. 33 31 INVENTOR. RAWOLT A. LABOMARDE BY 7 1 I ram-4M ATTORNEY/5' Oct. 28, 1958 R. A. LABOMBARDE 2,357,827

APPARATUS FOR FOLDING LEADING FLAPS Filed Aug. 9, 1954 v s Sheets-Sheet 2 RAWONDALABQMBARDE PM" WW ATTORZVEYS I Oct. 28, 1958 R. A. LABOMBARDE APPARATUS FOR FOLDING LEADING FLAPS 3 Sheets-Sheet 3 Filed Aug. 9, 1954 INVENTORQ 25 liAI YIIQAWA. LABOMBARDE 7 ATTORNEYS United States This invention relates to mechanism for folding the leading flaps of a plurality of flat articles such as box blanks advancing individually and successively along the paper line of a folding machine.

Many such mechanisms have been proposed for accomplishing the foldingof leading flaps which mechanism may be broadly classified as movable folding fingers traveling along with the blanks as in patents to Staude such as U. S. No. 2,291,063 of July 28, 1942, and movable folding fingers not traveling along with the blanks as in patents to Labombarde such as U. S. No. 1,370,654 of March 8, 1921. This invention is of the latter type and provides a folding finger mounted to move on a fixed axis located adjacent the paper line.

Of the various fixed axis folding fingers heretofore proposed, some trail downwardly and rearwardly behind the axis and hook onto the leading edge of theadvancing fiap as in the Labombarde patent above mentioned and some include a raised protuberance in the path of the flap to lift the flap into engagement with such a trailing finger as in patents to Nesmith, U. S. No. 1,538,298 of May 19, 1925, and to Wright, U. S. No. 830,032 of September 4, 1906. A folding finger extending forwardly and downwardly from a fixed axis is shown in the patent to Anderson U. S. No. 2,197,089 of April 16, 1940, but all of these fingers merely oscillate and do not have the advantageous feature of being rotary and thus permitting high speed accurate operation.

A solution to the problem of satisfactory high speed Operation of such leading flap folding devices has been proposed wherein a reversely rotating hooked finger is provided having a flap folding surface initially horizontal below the paper line, but movable to an increasing angle of elevation with the flap to deliver the flap to a notch in a folding bar. The upfolding of the flap, however, takes place in rear of the axis of rotation of the finger, the flapfolding surface thereof is not adapted to downfold as well as upfold, the shank of the hooked finger forms an obstruction at the end of the flap folding surface and the flap folding surface may drop a small flap or fail to support a flimsy flap throughout the fold.

In this invention, the folding finger is also rotatable around, rather than oscillatable on, a fixed shaft above and transverse to the paper line and is reversely rotated around the shaft as a fixed centre of rotation. However, the folding face, or surface, of the finger is substantially straight and adapted to guide a flap in front of, above and beyond the shaft in a substantially straight plane. The reverse rotation of the finger is timed to cause it to first present an upwardly inclined surface, in advance of its shaft, and with its terminal tip several inches in front of .the shaft and in the path of a leading flap whereby the flap slides up the surface and is upfolded when the flap, and its fold line, reaches the zone of the shaft. In view of the continued reverse rotation of the finger, the same flap folding surface, in the lower rear quadrant of its path, also serves to downfold the flap, thus eliminating any separate downfolding bar if desired, and completing the atent O 2,857,827 Patented Oct. 28, 1958 ice entire folding operation with a single finger. In addition, because the folding finger is provided with a folding surface tangential to its support, there is no obstruction thereon to the free sliding of the flap up and down said surface during folding, and no possibility of jamming or buckling the blank by reason of meeting such an obstruction.

Because the upfolding of the flap takes place while the finger is rotating downwardly and forwardly rather than upwardly and forwardly, the flap engaging surface of the finger is continuously in the path of all portions of the flap during its upfolding whereby the flap cannot be dropped, and cannot flip past the finger without folding.

The principal object of this invention is to provide mechanism and a method for folding the leading flaps of flat box blanks which mechanism is rotary in operation and capable of not only upfolding, but also downfolding a leading flap.

Another object of the invention is to provide a rotary flap folding finger that presents a forwardly and upwardly inclined surface to each approaching leading flap, then changes the angle of inclination of the surface to vertical and then changes to a rearwardly and downwardly inclined surface all while continuously engaging the flap.

A further object of the invention is to provide a straight flap folding finger rotating in a circular path principally above the paper line which finger not only lifts a leading flap from its flat position, but upfolds and assists in downfolding the flap with each revolution thereof.

Other objects and advantages of the invention will be apparent from the following description of a preferred embodiment thereof and from the claims appended hereto.

In the drawings:

Figs. 1-5 are side elevations, partly in section of a leading flap folding zone of a typical box folding machine with the folding mechanism of the invention shown in its successive positions of upfolding and downfolding a leading flap.

Fig. 6 is an enlarged view of a leading flap folding finger according to the invention.

Fig. 7 is a view similar to Fig. 6 of the folding finger of the invention arranged to accomplish two folds in one revolution of the shaft.

Fig. 8 is a perspective view of a folding finger of the invention having an adjustable flap stop attached thereto.

Figs. 914 are side elevations similar to Figs. l-5 illustrating the operation of the folding finger of the invention with the adjustable stop installed and used on'a'comparatively short leading flap.

Fig. 15 is a fragmentary side elevation of the leading flap folding zone of a folding machine showing the preferred drive mechanism of the invention.

Fig. 16 is a plan view of the mechanism shown in Fig. 15, and

Fig. 17 is a perspective view of the folding finger of the invention associated with the stationary downfolding member, an adjustable flap stop being mounted on the downfolding member.

In the drawings, only a leading flap folding zone of a typical box folding machine is illustrated since the mechanism and operation of such folding machines are well understood in the art, may be of any convenient type and form no part of the invention herein. There may be several leading flap folding zones in such a machine, each equipped with leading flap folding mechanism such as that shown and all operating in the same manner.

The box folding machine used for illustration is of the horizontal conveyor type and includes a frame 20 having parallel side frame pieces 21 and 22, suitable end pieces not shown and a plurality of rods and shafts extending transversely between the side pieces to support O the folding machinery. Endless conveyor means 23 extends longitudinally of the machine, receiving fiat blanks such as 24 individually and successively from a stack and conveying the same horizontally along a paper line such as 25 while folding machinery along the paper line folds the various tabs, flaps or panels to form a collapsed box, set up box .or similar folded article such as an envelope.

The paper line 25 is formed by the upp er stretches such as 26 of a pair of parallel endless .belts 27 .and 28. Each belt such as 28 is trained around suitable pulleys such as 30 and 31 carried on shafts such as 32 and 33, the shafts being driven in any convenient manner and synchronized with the other drives of the machine all in a manner well known.

It will be understood that oppositely disposed upper and lower conveyor chains may also be used to advance the flat articles individually and successively along the paper line, if desired.

Suitable holddown belts or bars such as the belt 34 may extend along the paper line 25 to hold down portions of the blanks while other portions are folded or to hold folded portions down after their folding. The blanks such as 24 include a main body 35, one or more leading flaps, tabs or panels such as 36, 37 and 38 articulated to the body on a transverse line of articulation 39 and may also include trailing flaps, tabs or panels such as at 40, 41 and 42 and wall panels 43 and 44. It will be obvious, however, that the function of this invention is to fold a leading flap, or other leading articulated portion of a blank that is advancing flatwise along a paper line and that the remaining conformation of the blank, or the other operations performed on the blank by the machine, are not relevant to a description of the invention herein.

The folding mechanism of this invention includes a folding finger 50, preferably of rigid material and mounted to rotate on an axis of rotation 51, the axis 51 being spaced above and extending transversely or laterally of the path of the blanks 24 on conveyor means 23 along paper line 25. Preferably the axis of rotation 51 is formed by a shaft 52 upon which finger is fixed by an integral sleeve portion 53, the finger 50 being split at 54 and tightenable thereon by set screws such as 55. Finger 50 is thus rotatable with shaft 52, the shaft 52 being journaled at each opposite end 56 and 5'7 on side frame pieces 21 and 22 and rotated by means to be hereinafter described. The folding finger 50 is elongated and provided with at least one. flap folding surface 58 which is preferably smooth, straight and leads to a point beyond the shaft whereby a flap being unfolded thereby may slide up to, and beyond, the shaft 52 in front of the shaft.

In accordance with the invention, the finger 50 rotates reversely around its axis of rotation whereby in the lower quadrants of its circular path it is advancing in the same direction as the blanks 24 on conveyor means 23. The flap folding surface 58 is thus a trailing face, or surface, on a finger continually rotating around a transverse shaft. It should be noted that the surface 58 inclines upwardly from the paper line to the level of the shaft, when meeting each successive blank and directs the leading edge of the leading flap thereof up beyond the point 59 as the finger rotates downwardly and rearwardly to a depending vertical position on the shaft. In operation, the reverse rotation of folding finger 50 is timed to cause the trailing, flap engaging surface 58 to present a forwardly and upwardly inclined surface to each approaching flat leading flap such as 36 or 37 with the free terminal tip 60 thereof just below paper line 25. In this position, the finger 50 is in advance of its axis of rotation 51 and a smooth unobstructed pathway is formed by trailing surface 53 up to and, if desired, beyond the shaft 52.

The forward component of the finger 50 in its reverse circular path is such that it is less than the rate of advance the leading flap such as 36 slides up the trailing surface 58.

The flap 36 bows and then bends on its line of articulation 39 as the finger 50 rotates therewith through the first lower quadrant of its circular path. As is customary with such devices, a fiap such as 36 or 38 is upfolded while holddown members hold down the blank along the longitudinal path of flap 37 and in a subsequent zone the flap 37 is upfolded while the blank is held down along the longitudinal path of the flaps 36 and 38.

When the trailing surface 58 of folding finger 50 has rotated reversely through the first lower quadrant of its path to about a vertical position, the flap being folded, such as flap 36, is nearly upfolded to a vertical position and its leading edge is well up surface 58 adjacent the shaft 52. At this point also, the line of articulation 39 of the upfolded flap such as 36 has just caught up to the trailing surface 58 of finger 50, whereupon the finger accelerates its rotation, in a manner to be explained, to cause the surface 58 to advance at the same rate of speed as that of the blank 24 and line of articulation 39. After the flap 36 is substantially vertical, the trailing surface 58 of finger 50 commences to assume a rearwardly and downwardly inclined position in the second lower quadrant of its circular path as indicated in Figs. 4 and 5. Trailing surface 58 thus forms a downfolding member and the undersurface 62 of flap 36 reverses its direction of sliding and commences to slide down surface 58. The finger 50 is timed to just clear the paper line 25 as the line of articulation 39 is advanced thereunder by conveyor means 23, at which point the completely downfolded flap 36 passes to the contol of suitable holddown members of well known type.

As shown in Figs. 15 and 16 the means for rotating finger 50 is preferably a first speed change cycle gear 63 mounted on shaft 52 and enmeshed with a second speed change cycle gear 64. Gear 64 is carried by a shaft 65, journalled in frame piece 21, shaft 65 carrying a sprocket 66 driven by a chain 67 and sprocket 68. Sprocket 68 is carried by shaft 33, the shaft 33 being driven by suitable drive connections 69 with a source of power not shown. The oval gears 63 and 64 cause the finger 50 to have two speed change cycles in each revolution where the finger rotates slowly through the first lower quadrant of its circular path and rotates more rapidly through the second lower quadrant thereof, thus permitting upward sliding of a flap without slowing down the rate of production of the machine.

As shown in Figs. 9-17 while trailing surface 58 is adapted to form a downfolding element in the second lower quadrant of its circular path, I may also provide a separate downfolding member to supplement this func tion or to entirely replace it. As shown, a metal strip 70 depends downwardly from a transverse frame piece 71 supported on frame 20 above shaft 52 and is arcuately bent at 73 around the axis of rotation 51 formed by the shaft 52. Thence strip 70 extends rearwardly and downwardly to a free terminal tip 74 proximate and just above paper line 25. Thus the undersurface 62 of a leading fiap 82 is upfolded by sliding up the trailing surface 58 of finger 50 until it is vertical and then is downfolded by sliding down surface 58 as well as down underface 76 of strip 70. As the finger 50 continues on its circular path and clears the path of the blanks, strip 70 and its underface 76 continue to press the flap 82 down on the line of articulation 88 into downfolded position.

It should be noted that the forward face 75 and the underface 76 of strip 70 are each tangential to the curved face of an imaginary cylinder encircling shaft 52 whereby elongated flaps meet with no obstruction and may freely slide therealong. Preferably, strip 70 includes an elongated central slot 77 within which slot the finger 50 is accommodated. The trailing surface 58 of finger 50 thus merges with the forward face 75 of strip 70 to permit flaps of various lengths to fold to vertical position without obstruction and surface 58 also merges with the underface 76 of strip 70 when delivering a downfolded flap thereto.

As best shown in Figs. 6 and 7, the preferred form of folding finger 50 is split from tip to base to form two identical halves, 80 and 81. When assembled as in Fig. 6 only trailing surface 58 is effective for flap folding, and with oval gears, one of the two speed change cycles occurs in the upper quadrants of the finger path to no folding effect. However, as shown in Fig. 7, by reversing the two halves 80 and 81, the surface 81 also becomes a trailing flap folding surface similar to surface 58 and two folds may be accomplished with each revolution of shaft 52.

In Figs. lthe folding finger 50 is illustrated as folding an elongated leading flap 36such as are used in Himes type paper boxes and, as indicated, the leading flap may freely slide beyond and above shaft 52. In Figs. 9-14, a blank such as 83 is shown, having a short leading flap 82 and with such blanks it is preferred to provide an adjustable flap stop element 84. Stop element 84 is a block having an elongated slot 85 for a setscrew 86 threaded in the trailing fiap folding surface 58 of a finger 50. Stop 84 may thus be fixed at various heights along finger 50 to form an abutment to engage the leading edge 87 of each successive flap 82. As shown in Fig. 11, stop 84 rotates reversely with the finger 50 to engage leading edge 87 when the flap 82 has slid well up trailing surface 58 and causes a positive fold along the correct line of articulation such as at 88. Stop 84 is rotating downwardly at this point, thus forcing the flap and blank down on the paper line.

As shown in Figs. 15 and 17, a stop 90 similar to stop 84 may be mounted on strip 70 for the same purpose, but it is preferred to mount the same on the rotating finger because of the advantageous downward push on the leading edge of the flap secured thereby.

In operation it will be apparent that the folding finger 50 does not merely hook onto the leading edge, or pull the undersurface, of the leading flap of an advancing blank up into contact with a downfolding bar and neither does it push up on the undersurface of a leading flap with a kicking action. Instead, folding finger 50 forms an inclined barrier extending up from paper line 25 as it advances with the leading fiap and as the flap slides up the folding surface thereof and continues advancing with the flap as the flap slides down the folding surface. The flap may therefore be under control of the same folding surface at all times and need not be passed therefrom to some other surface. Because there need be no obstructions on the flap folding surface of the folding finger and no other members to which the flap must be passed, a single finger may be used with flaps of various lengths longitudinally.

I claim:

1. In a folding machine, mechanism for folding the leading flaps of flat articles, said mechanism comprising conveyor means on said machine for advancing a plurality of flat articles individually and successively along a path with the lines of articulation of the leading flaps thereof lateral to said path; a rotatable finger non-yieldably mounted to rotate in a vertical plane longitudinally of said path around an axis of rotation above and lateral to said path, said finger having a straight fiap-engaging trailing surface extending in a radial plane outwardly from said axis of rotation and of greater length than the distance between said axis of rotation and the path of said articles; and timed driving means synchronized with said conveyor, said driving means continuously rotating said finger in a unidirectional, circular path with the trailing flap engaging surface thereof advancing in the lower quadrants of said circular path in the same .direction as, and at a continuously changing angle of inclination to thepath of, the leading flap of each successive article at a rate of advance less than the rate of advance of the flap in the zone of said article path immediately in front of the axis of rotation of said finger for presenting an upwardly inclined folding surface therein along with said flap is slideably supported and upfolded and at a rate of advance at least equal to the rate of-advance of the flap in the zone of said article path immediately in rear of the axis of rotation of said finger for presenting a downwardly inclined folding surface therein along which said flap may slide and be over folded.

2. Mechanism as specified in claim '1 wherein the means for rotating said finger includes a shaft upon which said finger is fixed, a first speed cycle change gear carried by said shaft and a second speed cycle change gear enmeshed with said first. gear for accelerating and decelerating the rotation of said finger in its circular path to enable said finger to form a forwardly-inclined upfolding guide in front of said shaft and a rearwardly inclined down folding guide in rear of said shaft.

3. Mechanism as specified-in claim 1 wherein said rotatable finger includes two oppositely disposed, trailing, flap engaging surfaces and said timed driving means includes a pair of speed change cycle gears accomplishing a speed change cycle for each trailing surface during each complete revolution of said finger for permitting two successive leading flaps to be completely over folded in each rotation of said finger around its axis of rotation.

4. Mechanism as specified in claim 1 plus a leading flap stop on the trailing flap engaging surface of said rotatable finger for engaging the leading edge of a leading flap and pushing down thereon to cause a positive fold on the line of articulation of the flap and set screw means on said finger for adjusting the location of said stop along said flap engaging surface.

5. Mechanism as specified in claim 1 plus a leading flap stop on the trailing flap engaging surface of said rotatable finger, said stop comprising a block having an elongated slot and a set screw threaded in said face and slideable in said slot for fixing said block in predetermined positions along said trailing surface.

6. Mechanism as specified in claim 1, plus separate flap downfolding means, cooperable with said finger, and including a stationary, longitudinally slotted, unitary strip of self supporting material mounted on the frame of said machine, said strip straddling the circular path of said finger and having a portion arcuately bent under said axis of rotation and then extending tangentially thereto, rearwardly and downwardly to a terminal end positioned just above the path of said blanks.

7. Mechanism as specified in claim 6 wherein said strip includes a portion extending tangentially upward from the axis of rotation of said finger for forming a fixed substantially vertical barrier to the leading edge of an upfolded flap.

8. Mechanism as specified in claim 7 wherein the upwardly extending portion of said strip includes a longitudinally slideable stop block adapted to be fixed in various positions therealong for intercepting the leading edge of a leading flap upfolded by said rotatable finger.

9. Mechanism for folding the leading flaps of a plurality of fiat box blanks advancing individually in timed succession on an elongated conveyor, said mechanism comprising a rotating, substantially straight finger describing a circular path in a longitudinally extending vertical plane around a shaft supported laterally above said conveyor, sai-d shaft being at less height above said conveyor than the height of an upfolded leading fiap for forming a flap downfolding barrier and said finger being of greater length than said height of said shaft to cause its terminal tip in its circular path to reach below the conveyor well in advance of said shaft and timed driving means, synchronized with said conveyor, for rotating said finger into and out of the path of the leading fiap of each approaching blank with said finger presenting a forwardly and upwardly inclined plane supporting surface nearly the length of a flap to each approaching fiap in advance of said shaft which surface advances with the flap while upfolding the same and downfolds the fiap while progressively changing to a rearwardly inclined surface until the flap departs therefrom.

l0. Mechanism for overfolding a leading articulated flap of a flat box blank while the blank advances along the paper line of a folding machine at a uniform speed, said mechanism comprising a rotatable shaft extending transversely of said machine and spaced above the paper line, a finger fixed to said shaft to rotate therewith in a circular path in a vertical plane, said plane extending in the direction of travel of said blanks and said path ex tending from Well above to slightlybelow the paper line, said finger having ,a straight trailing surface and timed drive means unidirecti-onally rotating said finger in advance of said shaft and in the path of the leading flap of said blank at aless speed of advance than that of said blank to cause the leading flap to slide up said surface and be upfolded thereby in advance of said shaft and rotating said finger at greater speed in rear of said shaft to cause said leading flap to then slide down said surface S and be downfolded downwardly thereby in rear of said shaft.

11. In a folding machine having conveyor means for advancing a plurality of fiat articles individually and successively along a path With the lines of articulation of the leading flaps of said articles transverse to said path, the combination of leading flap folding means synchronized with said conveyor means and including a single flap folding finger rotating in timed relation with said conveyor around an axis of rotation transverse to said article path in a circular path which intersects said article path and is co-directional therewith in its lower quadrants, said finger accompanying; supporting and upfolding a leading flap inthe forward lower quadrant of its circular path and accompanying; downfolding and releasing said flap in the rearward lower quadrant of its circular path.

References Cited-in the file of this patent UNITED STATES PATENTS 1,974,408 Bergstein Sept. 25, 1934 2,054,406 Betts Sept. 15, 1936 2,598,809 Liebl June 3, 1952 2,647,447 Andre Aug. 4, 1953 

